HP Pavilion ze2805 shuts down after 10 min to 7 hrs of operation
 

When I first received it (used) a few weeks ago, this only happened occasionally and it took a while for a pattern to develop. The 7 hr stretch was listening to music of WCPE.org, but the next day I only could get minutes from the same site. It sems to get progressively worse, yet the outside of the case, near the fan or anywhere else, doesln't get uncomfortably warm. I had another unit from the same vendor. He took that back and sent this one after a 24'hour test, but will not answer further communication. Generally I get best results if it has sat shut down overnight, but this morning even that was good for only a few minutes. It does this running XP from the hard disk or Linux from CD. Actually I would like to split the hard disk and put Linux on the second half as the default boot. But it won't run long enough to install anything now!

It sounds like you have either a heat problem, a power supply problem, or a defective motherboard component.

To check the heat management do this:

1) Open the case and check to see that the CPU cooler is not broken. Ensure that all of the mounting points are not broken. Then get a can of compressed air and blast the CPU cooler.

2) Ensure that the CPU cooler fan works when you turn the computer on.

3) Ensure that the case fans are working.

If that doesn't fix it then if you have a spare power supply try using that in the computer.

If that doesn't fix it then you may have to replace the motherboard.